Drive-shoe.



am I

Sdi, Hu;

reame? Ww sho?a 5 teet Ath,d speci ce is i0 furled 1n 'YU Y,

The

@ cat-lon,

reemer is employedin connection with the shoe. Thus the teeth 18 arefully-protected frein' the blows of the under-remner bits. lt will beobserved that 'come of the cut-4 '5 ters in the ,lowermost .convolutionof the spiral series, 'es seen at 14?, ere iforrned jointly with theediecent fece teeth 18a. will be noted eiser( Figs. l and-$5)I that thefirst ree-ming cutter Mb tiene lower end of the'spirel series, togetherwith the adje,- eent face-tooth 1S", res t in e'plowshere formation onthe edv-ence cutting element, the scid tooth b being continued acrossthe nent adjacent notcli lo.

f The provision otspirel roaming elements on; theexte'rior sidesurireceof the shoe remlts'inigving. u'- turning movement to the whole. 'stringor cesin sections in spudding or' letting the casing down on thebottom'oi-the drill hole. A. furtlier advantage ettending the spiralelements es comp-,tred y '.fvith the ordinary bell slice, is that thelife Jef the shoe is prolonged in proportion to the "numEer of cmvolutions,` since the 4first convoluion will weer rst by reason ofbeering the brunt of the cutting action, the secl ond convolution being`then subjected to the greatest Wear, und so on. Approximately threeconvolutions are preferred. The spirai rib presenting more or less of oconvolgtion of unbroken continuity will, in oddition to sustaining itsproper proportion or weer, serve to cleer the hole of any projectionsleft by the seperate cutters 14.

By the described construction the drive Shoe will in many ceses,sul'lice to produce the necessery'reeming action to accommodatethe'cesing end its collars, etc., Without the employment of en"under-reculer.

4The lateral cutters er'enged in e. spiral series es described, it willbe seen, results in eA progressive cutting action liy the succes sivecutters in e convolution, considering;

a turning movement of the tool through u, given annuler zone, thecutters serving; to successively cut portions in the given of action.

The formation of the lateral teeth with interdentel spaces gives theseries of teeth the forni of e broken squere thread, the opposed wallsof the two adjacent teeth being formed by the side Wells of enintervening space and the teeth on the 'Front fece merging into theforward teeth of the spiral, 55 The result obtained is that the teethuct as 4* teaming cutters distinguished from. -oro ducing' a. merebreaching action. Again, the spiral series of teeth, defined by the interdental spaces to present e broken square thread, result in cuttershaving pronounced. forward cutting action, but c negative rake forreverse. Als0,`the very important result is obtained, that tileV casingis automatically rotated Within certain limits, giving e ri-' 11mgefect-Fuftherrnore, the shoe Wil have ,err

`on en earth Well e plestering eect Aso that the well will stond upbetter.

Hoving thus described my invention, l

claim es new, and desire to secure by Letm Vters Patent:

l. A drive shoe. for Well casings having reeming cutters on the outerside thereof,

the cutting edges of which are spirally dis! lposed.

outer side thereof, and s spiral groove, the I convolutions of whichalternate with the.

convolutions of the roaming cutters, there being spaces alternating withthe cutters and intersecting the said groove.

4. A drive slice for Well cusings, having on the front iace en annularseries of cutting teeth seperated by intervening spaces, and on theouter side having lateral reeming cutters, the seid roaming cuttersdisposed in the form of e spiral series, the said front teeth merginginto the forward teeth of the spiral. series.

5. A drive shoe for Well cesings, having on the front fece thereof enannularseries of cutting teeth, and e plane seat radially inv/:1rd fromthe cutting' teeth adopted' to scot; under-reemcr elements.

6. A drive shoe for well cusings, having on the front fece thereof enannuler series oifr cutting teeth, and lute ul roaming cutters on theouter side of t'ne shoe, the said teeth und cutters presenting cuttingedges form 'part of e cylindrical surface'.

7. A drive shoe for Well, casinos, lievi/'ing on the outer surfacethereof e. spiral series being" l ice of reeining cutters beveled. onthe outer surfeces, the lower 0it tlie several cutters forming part oi?e. cylindrical surface.

8. A. drive shoe 'for Well cesingsllie.ving ou the outer eide thereof anannuler" spiral series of separated resiningr cutters presenting eplurality ot convolutions, the cutters ci one convolution of tue spiritiseries being in stugrgered relation to the cutters of en adjacentconvolution oi seid series. I

9. drive slice for Well carvings, leaving on the outer side thereof uspiral series of seperate rceming cutters, and a' sbirel ril) continuouswith the uppermost convolution of the series of cutters.

T10. A drive slice for Well cesings, having/1 on the outer thereofspiral series of reeming cutters, und un annuler series of cuttinglteeth ou the iront foce ci the slice, certain of said teeth being formedcontinu*- ous with certain of the cutters in the lovrerf mostconvolution of. the spiral series of cutters, Seid cutters en the frontlieee of the lil@ mee

shoe terminating at their inner sides, outward from the here of theshoe.

1l. A drive shoe for well casings, having a spiral series o' roamingcutters ohliquely disposed on the outer side thereof separated byintervening spaces, and an annular series of cutting teeth on the frontface of the shoe, one of the said teeth being formed in conjunction withthe irst cutter in the lowermost convolution, and extending across thespace between the two adjacent cutters in the next convolution.

12. A drive shoe for well casings, having a, spiral series of reaiuainrcutters on the outer side thereotl and a spiral groove, the convolutionsof which alternate with the convolutions o the cutters7 and a spiral ribpresenting a convolution continuous with the spiral series of cutters,the said groove being continued above the said ril).

13. A drive shoe for Well casings having lateral cutters on theouteifside thereof rearH ward of the front end, and a rib on the eX-terior surfaces above the said cutters, the rib and cutters presentingedges7 forming part oi' a cylindrical surface.

14; A drive shoe for vvell casing. having a toothed front cutting edge,lateral cutters on the outer side of the shoe rearward of the said frontcutting edge, and a rib on the exterior surface above the said lateralcutters.

In testimony `whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

H. MEAD.

